Process of and apparatus for making soap



Feb.* 7, 1939. B H. THURMAN 2,146,661

YROCESS OF AND APPARATUS FOR MAKING SOAP Filed May 13, 1935 lug?- hug- (Sf/van M/N H. 771uRMA/v A TTOR/VEY.

Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE PROCESS OF AND FOR MAKING of Nevada Application May 13, 1935, Serial No. 21,144

9 Claims. (Cl. 260-418) My invention relates to a process for the manufacture of soap, and more particularly to a process in which impurities may be removed from the soap after saponification.

Soap is produced by the saponification of fats by suitable reagents and for all purposes herein the term "fat is defined as including all those fats, oils, and other substances which may be used in soap manufacture, including, for example, animal fats, vegetable oils and fats, and fish oils.

The term reagent as used herein includes all those substances which are adapted to produce a saponification of fats, such as, for example, caustic potash or caustic soda in aqueous solution.

The term purifying agent as used herein is defined as including all those substances which are adapted to remove impurities from fats, soaps or glycerine when used in connection with the hereinafter described process.

It is an object of my invention to provide a process whereby raw fats or fats in a partially purified state may be-saponifled with a reagent to produce a soap, which soap may then be purified and subsequently finished.

It is a further object of my invention to provide a process whereby raw or partially purified fats may be saponified with a reagent to produce a soap in a liquid state, which soap may then be purified to remove impurities, and the resulting soap further acted upon to give it a predetermined moisture content.

It is a still further object of my invention to provide a substantially continuous process of making soap, including the steps of continuously mixing a raw or partially purified fat with a reagent, continuouslysaponifying the mixture of fat and reagent to produce soap,purifying the resulting soap, and continuously passing the purified soap through a moisture content control device to, 40 produce a finished soap having a predetermined moisture content.

Further objects and advantages of my invention will be evident from the following disclosure and the claims. Referring to the drawing which shows an apparatus which I preferto use in the practice of my invention, but which is for the purpose of illustration only:

Fig. l is a diagrammatic general assembly view in elevation of the apparatus, a portion of this apparatus being shown in section.

In Fig. 1 of the drawing, I show a mixing ap- V paratus H), a primary heater 20, a purifying means 30, a secondary heater l0, and a separating chamber 50.

The mixing apparatus consists of an alkali pump l i and a fat pump I2, the pump i 2 being driven by a suitable motor l3 and the pump l I being driven through a variable speed transmission it, which may be made in the form of a speed 5 changing gear, from the pump l2. The fat which it is desired, to convert into soap is taken from a fat tank It and pumped into a mixer I! by the pump l2. An alkali tank i8 contains an aqueous solution of a saponifying alkali or reagent such 10 as. caustic soda in water, the pump ll taking the aqueous solution or reagent from the tank I8 and pumping it into the mixer IT. The mixed fat and reagent pass through a pipe i9 to acoil 2| of the heater 20.

The primary heater 20 consists of an outer shell 23 in which the coil 211$ placed, and a burner 2| supplied with fuel through a fuel valve 25. Gas, oil, or any other suitable combustible material may be used as fuel, this fuel being ignited 20 at the burner 24 and the hot products of combustion passing upwardly inside the shell 23 and supplying heat to the coil 2|. In the coil 2i a reaction takes place in which part or all of the fat is saponifled to form soap, glycerine, water 5 vapors, and residue fats, hereinafter termed the reaction products". The reaction products are deliveredthrough a pipe 26, having a pressure gauge 21 and a thermometer 28 therein, to one or more of a plurality of soap kettles or tanks 30 3! comprising the purifying means of my invention.

Between the kettles 3i and the pipe 26, I provide valves 32 which may be opened as desired to permit the reaction products to flow into one or more 35 of the kettles. Although in the drawing I show two kettles 3| connected to the pipe 26, it is to be understood that any desired number of kettles may be connected in like manner without departing from the spirit of my invention, and, in practice,

it may be desirable to use a large number of such kettles.

The kettles 3| may be made in any form suitable for soap purification, but I prefer to make them with outlet pipes 33 through which the purified soap may be led out oflthe kettles, and brine pipes 34 through which brine or other purifying agent may be introduced into the kettles from a suitable source of supply for use in the purification or salting-out operation. The kettles 3 I, if desired, may be provided with appropriate venting means to permit steam or other vapors to escape therefrom, or may be so constructed that the contents thereof are in open communication with the atmosphere. The reaction products are admitted to the kettles through inlet pipes 35. The outlet pipes 33 are connected through valves 36 to a soap pipe 31 having a soap pump 38 therein driven by a motor 39. The outlet pipes 33 are also connected through valves 36a to a waste pipe 31a through which brine, impurities, glycerine waters, and other undesired sumtances may be drawn off from the kettles 3| and separated from the purified soap. The soap pump 38 is preferably a gear or screw pump capable of handling the purified soap coming from the kettles 3i and forcing it through the soap pipe 3'! and delivering it to the coil 4! of the secondary heater 40.

The secondary heater 40 consists of an outer shell 42 housing the coil H, and a burner 3 supplied with fuel through a fuel valve M. Any suitable fuel may be used in the burner 43, although I prefer to use gas or oil which may be supplied from the same source as that which supplies the burner 24, this fuel being ignited at the burner and the hot productsoi combustion passing upwardly inside the shell 42 and supplying heat to the coil ll. In the coil 4| the purified soap is heated to a desired temperature and is delivered through a pipe 45, having a pressure gauge 46 and a thermometer 41 therein, to a nozale 5! in the separating chamber 50.

The separating chamber 50 consists of a shell 52 inside of which the nozzle'5l is carried. The nozzle 5! is preferably comprised of a metal memher having a constricted orifice through which the soap must pass. A suction blower 53 is connected to the shell 52 so that air and steam may be exhausted therethrough from the chamber 50 as desired, and a wing-valve 56 is placed in the bottom of the chamber so that the finished soap may be withdrawn therethrough from the chamber. 7

The method of operation is as follows:

The tank is is filled with the saponiflable iat which it is desired to convert into soap and which may contain undesirable foreign matter or coloring, this fat being heated by any suitable heating means if necessary to'a point at which it is liquid. The tank l d is filled with an aqueous solution of a reagent or saponiiying alkali, such as, for example, a solution of caustic soda in water. The fat is pumped into the mixer I! by the pump l2 and the reagent or alkali is pumped into the mixer l! by the pump ii. The variable speed transmission l8 may be adjusted so that the proportion of alkali supplied to the mixer l! is only slightly in excess of that theoretically necessary to saponify the fat completely. The pumps H and 12 may be piston pumps but shouldbe of such type that they can pump against several hundred pounds per square inch pressure. The mixture of saponifiable fat and saponiiying alkali is delivered through the pipe to the heater and is heated therein by the products of combustion from the burner M.

In the coil ill reaction takes place between the saponifying alkali and the and reaction products including soap and glycerine are formed. The reaction products may also contain impurities and other substances. Suiflcient heat is supplied to the mixture in the coil 2% to raise the temperature or" the reaction products passing through the pipe 26 to a point at which the reaction proceeds rapidly, which temperature is indicated on the thermometer 28. The pressure in the pipe 26 is indicated by the gauge 21'. The soap and glvcerine issuing through I the pipe 26 may contain matter which it is de saponifiable fat,

sired to remove by purification, such as, for example, coloring or odoriferous matter, although some purification of the fat and soap may take place during the saponiiication of the fat in the coil 2|.

One of the valves 32 is opened and the reaction products are permitted to pass into the kettle 30. The outlet valves 36 and 36a to the kettle are closed and the kettle is filled to a desired point, at which time the inlet valve 32 of the filled kettle is closed and the reaction products in the pipe 26 are then conducted to another kettle which is filled in the same manner. By providing a suflicient number of kettles 30, and by replenishing the supplies of fat and reagent in the tanks 16 and I8 as becomes necessary, the saponification operation in the coil 2| may be conducted continuously, the reaction products being conducted to the kettles in sequence. It is to be understood that several kettles may be filled at a time without departing from the spirit of my invention, and that although I prefer to operate my process continuously by filling the kettles in sequence, an alternative method of operation is to fill the kettles simultaneously, or nearly so, and

conduct the saponification only intermittently to provide a process in which the reaction products are made and the soap purified in batches.

A purifying agent, such as brin". is passed into the kettle 30 through the pipe 3-., and this may be done before, during, or after the kettle is filled with the reaction products, as desired. After the brine or other purifying agent is mixed with the reaction products in the kettle 30, a reaction takes place, often termed salting out" in the trade, during which the impurities settle to the bottom of the kettle together with the giycerine in the reaction products. When the salting-out operation is completed, the brine, glycerine, and impurities are drawn oil from the kettle 30 by opening the valve 36a and allowing them to be removed through the pipe 31a, and the valve 360. is then closed again and the valve 38 is opened. As soon as the valve 36 is opened the purified soap may be pumped out of the kettle 30, through the pipe 31, and to the coil H of the secondary heater 4!! by means of the soap pump 38 which develops sufdcient pressure to remove the soap through said coil and its associated nozzle 51.

In the coil 4! the temperature of the purified soap is raised, and it is then delivered through the pipe to the nozzle 5! of the separating chamber 50. The soap emerges from a constricted orifice in the nozzle Si in the form of a high velocity jet containing steam and particles of liquid soap. The soap is precipitated to the bottom of the separating chamber and in its passage through the chamber the steam escapes therefrom, being withdrawn from the chamber by the suction blower 53. The solid soap particles are collected in the bottom of the separating chamber, and are withdrawn therefrom as desired through the wing-valve 54.

It will be clear that by providing a suillcient number of kettles 30, and by purifying their contents in sequence, a continuous flow of purifled soap can be maintained in the pipe 3i. As soon as one kettle has been emptied of its purified soap through the pipe 31', another kettle outlet valve 36 may be opened and the purified soap of its kettle can be drawn oil through the pipe 37. Of course, as soon as one kettle is emptied, its valve 36 is closed, its inlet valve 32 is opened, audit is again filled with unpurifled reaction ing zone so that at the pressure existing in said products and purified as described hereinabove. This provides a continuous soap making process.

By regulating the temperature and pressure in the coil 4| of the secondary heater 40 by controlling the amount of heat supplied thereto by the burner 43 or otherwise, the soap collected in the separating chamber 50 can be given any desired water content.

I claim as my invention:

1. A process of making soap, which process includes the steps of: passing a mixture of reagent and fat containing undesirable impurities through a heating zone in which a substantial proportion of said fat is saponified to form reaction products including soap, glycerine and other undesirable impurities; removing said glycerine and said other impurities from a mass of said reaction products to form a purified soap containing considerable ,moisture; pumping a stream of said purified soap through a second heating zone under pressure; introducing this heated stream of purified soap into a separating chamber in which the pressure is below the pressure existing in at least a portion of said second heating zone; controlling the amount of heat added during passage through said second heat separating chamber at least a portion of the moisture in said stream of purified soap is in the form of vapor; and separately removing said vapor and said soap from said separating chamber.

2. In an apparatus for making soap, the combination of means forming a mixture of fat and reagent; a heater associated with said means and through which a stream of said mixture passes to be heated and saponified to form a stream of reaction products; a plurality of soap kettles; means discharging said reaction products selectively into said soap kettles for such purification as will produce a purified soap having an excess of moisture; pump means selectively withdrawing said purified soap from said kettles to form a continuously-flowing stream of said purified soap; heating means receiving said continuously flowing stream of purified soap and heating said purified soap to such degree that water vapor will be liberated upon reduction in pressure on said purified soap; and a separating chamber into which the heated soap discharges, the pressure in said separating chamber being lower than the pressure in at least a part of said heating means to permit separation of water vapor from said soap.

3. A process of making soap, including the steps of: continuously passing a mixture of fat and reagent through a heating zone in which said fat is saponified to form reaction products including soap, glycerine and impurities; discharging said reaction products into a purifying chamber; purifying said reaction products in said chamber by adding a purifying agent capable of settling out glycerine and other impurities from the reaction products while these reaction products are in said chamber thus separating same into purifled soap containing an excess of moisture and a material containing said glycerine and said impurities; withdrawing said purified soap -from said chamber while containing said excess of moisture; forming a stream of the purified soap with its excess moisture and discharging same into a separating chamber; heating said stream before discharge into said chamber to a temperature above the temperature at which water will vaporize at the pressure existing in said separating chamber'whereby a portion of said excess moisture vaporizes; and removing water vapor from said chamber.

4. A process of making soap from raw or partially-purified fats, which process includes the steps of: moving a mixture of fat and reagent through a heating zone under pressure while applying sufficient heat to effect saponification and form glycerine but insufiicient tovaporize said glycerine in said heating zone thereby forming a stream of reaction products including soap, glycerine and impurities, which impurities include color impurities; mixing brine with said reaction products and allowing the resulting mixture to settle into a layer of purified soap containing an excess of moisture; withdrawing said purified soap while containing said excess of moisture;,

5. A process of making soap, including the steps of: continuously introducing a mixture of reagent and fat containing undesirable impurities into a primary heating zone under sufficient pressure to force same through and from said heating zone; applying heat to said heating zone so as to continuously saponify at least a substantial proportion of said fat and continuously form a stream of reaction products containing soap, glycerine and other undesirable impurities; batch-processing said stream of reaction products by collecting same in a plurality of batches and mixing therewith a purifying agent capable of settling out said glycerine and said other undesirable impurities to form a layer of material containing glycerine, impurities and said purifying agent; removing said layer of material from each of said batches, leaving a plurality of batches of purified soap containing excess moisture; withdrawing purified soap from said batches in such manner as to provide a continuous flow of purified soap; passing said continuous fiow of purified soap through a secondary heating zone; continuously ejecting said purified soap into a separating chamber; and controlling the moisture content of the finished purified soap by controlling the temperature of the soap so ejected and thus controlling the amount of Water which is so vaporized.

6. A process of making soap, which process includes the steps of: saponifying a mixture of reagent and fat in one zone under elevated temperature to produce reaction products including soap, glycerine and other impurities; moving the saponified product into a purifying zone and there removing glycerine and other impurities from a mass containing the soap of said reaction products; pumping a stream containing the purified soap and an excess of moisture through a heating zone while heating it therein; introducing this heated stream of purified soap into a separating chamber in which the pressure is below the pressure existing in at least a portion of said heating zone; and separating the excess moisture from the soap in said separating chamber to produce a soap of the desired moisture content.

7. A process of making soap, which process includes the steps of: forming and saponifying a mixture of fat and reagent and applying heat to the products while flowing as a stream in an elongated passage to produce a heated stream of reaction products containing soap and impurities; introducing this stream into a purifying chamber and introducing into this chamber not later than during the time of introduction of said stream an aqueous purifying agent capable oi combining with the impurities; settling the treated reaction products to separate the impurities from a soap mass containing excess moisture; and spraying a stream of this soap into a separating chamber and there separating from the soap the excess moisture to leave a soap product of desired moisture content.

8. The process of making soap, which process includes the steps of forming and saponifying a mixture of fat and reagent and applying heat to the products while flowing as a stream in an elongated passage to produce a heated stream of reaction products containing soap and impurities; introducing this stream into a purifying chamber and introducing into this chamber an aqueous purifying reagent capable of combining with the impurities; settling the treated reaction products to separate the impurities from a soap mass containing excess moisture; and spraying a stream of this soap into a separating chamber and there separating from the soap the excess moisture to leave a soap product of desired moisture content.

9. A process of making soap, including the steps of: continuously passing a mixture of fat and reagent through a heating zone in which said fat is saponifled to form reaction products including soap, glycerine and impurities; discharging said reaction products into a purifying chamber; purifyingsaid reaction products in said chamber by adding a purifying agent capable of settling out glycerine and other impurities from the reaction products While these reaction products are in said chamber, thus separating the same into purifled soap containing an excess of moisture and a material containing said giycerine and said impurities; withdrawing said purified soap from said chamber while containing said excess of moisture; and spraying a stream of said soap containing an excess of moisture into a separating chamber and there separating from the soap the excess moisture to leave a soap product of desired moisture content.

BENJAMIN H. 'I'l-IURD/IAN. 

